EP 0 787 084 B1 discloses a hydraulic unit of the indicated type which includes a ventilation system with one single ventilation point to the atmosphere aligned coaxially to the motor accommodating bore for the purpose of central ventilation of the accommodating bores. To this end, the motor accommodating bore is configured as a through-bore in the accommodating member. The rear portion of the accumulator accommodating bore is ventilated by way of a complex channel system, comprised of a transverse channel and ventilation slots provided between the motor flange and the accommodating member and between the motor mounting support and the accommodating member.
As an alternative to this presented ventilation concept, another embodiment of EP 0 787 084 B1 discloses connecting the rear chamber of the accumulator accommodating bore directly to the hollow space in the hood which is in fluid-tight abutment on the first housing surface of the accommodating member. Pressure compensation takes place by way of a ventilation point disposed in the hood. Leakage fluid of the pump is not hindered to propagate through the motor accommodating bore into the hood. Said hood accommodates electric and electronic components being disadvantageously exposed to moistening by fluid.
In view of the above, an object of the invention is to improve an immersion-proof hydraulic unit of the indicated type in such a fashion that the ventilation system can be manufactured in a simplified way, with the aim of avoiding the above-mentioned shortcomings.